FORMATION OF SUMMER RAIN FLOODS ON THE CHITA RIVER (TRANSBAIKALIA)

Abstract

Floods caused by rain floods in flood-hazardous regions, which include the Trans-Baikal Territory, lead to significant socio-economic and environmental consequences, especially for settlements located in floodplains. In the Trans-Baikal Territory, its administrative center, the city of Chita, located on the banks of the Chita River, is suffering the greatest economic damage. Therefore, the identification of the patterns of formation of floods on this river determines the relevance of this work, the task of which is to analyze the rain floods on the Chita River – the city Chita for the period from 1988 to 2017 during years of extremely high water consumption, as well as the amount of precipitation due to which they were caused. The work uses the observational data of the Trans-Baikal Administration for Hydrometeorology and Environmental Monitoring at the hydrological post of the Chita River – the city Chita and the Chita weather station. As a result of the analysis, it was revealed that the most significant floods were re-corded in the last high-water phase of the cycle from 1988 to 1998. Water consumption in 1991 was the first among the observed maximum values on the Chita – Chita River for the entire observation period, 1988 – the third, 1990 – the fifth and 1998 – the seventh. The main factor in the formation of flood waves during these years was precipitation, which in the months of recorded maximum water discharge was 50-165% more than normal, while the daily amount in the period before the flood reached 30-62 mm. A characteristic feature of the formation of floods in the Trans-Baikal Territory, in particular, on the Chita River, is the deep southern or south-western cyclones emerging on its territory. Long-term active cyclonic activity over the Trans-Baikal Territory in the summer leads to rainfall, which cause a sharp increase in water discharge to extreme values.